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POPULAR SCIENCE MONTHLY. 



about two volts. Having constructed his 

 accumulator, Plante experimented with vari- 

 ous methods of "forming" the plates that 

 they might yield effects extending over a 

 considerable interval of time. His method 

 was to pass a current through the accumu- 

 lator first in one direction, then in the other, 

 and repeat this reversal many times with 

 intervals of rest in between. The only cur- 

 rent available for this work was that ob- 

 tainable from a primary battery ; this made 

 the process a long and expensive one, but by 

 its means currents of considerable density, 

 lasting for a length of time depending on 

 the extent to which the plates had been 

 affected by the electrolytic process, were ob- 

 tained. Between 1859 (when Plante began 

 his experiments) and 1880, when Faure in- 

 vented the pasted battery, great changes had 

 taken place in the condition of the elec- 

 trical arts and manufactures. The dynamo 

 had been perfected, and offered means for 

 the cheap production of currents of great 

 density and high E. M. F., and hence gave a 

 new stimulus to the production of a practi- 

 cal storage battery. Faure made pastes of 

 red lead and litharge, which he applied to 

 the surfaces of the positive and negative 

 plates. When these were subjected to the 

 forming process, the red lead was oxidized 

 to peroxide and the litharge reduced to 

 spongy lead, with a material saving in time 

 and cost over the Plante process. Almost 

 immediately accumulators were put to a 

 variety of industrial uses, among which may 

 be mentioned their application to carry the 

 day load in lighting stations and to pre- 

 vent the necessity for running dynamos at 

 night in private residences. Even for trac- 

 tion purposes, where accumulators are sub- 

 jected to the severest demands, their use 

 was proposed as far back as 1880, and in 

 1883 a car went into service at Kew Bridge, 

 London, equipped with a Siemens dynamo, 

 set to run as a motor, and about four thousand 

 pounds of batteries. The first storage bat- 

 tery put upon the market was, of course, 

 crude, and the result was that in nearly all 

 of its various applications it was a failure. 

 The modern storage battery dates from the 

 invention of Faure in 1880, and up to within 

 a few years the pasted lead battery was the 

 only form used to any extent. Recently the 

 Plante type has again come into favor, to- 



gether with an improved form of battery 

 known as the chloride accumulator. The 

 characteristics of the Plante type of battery 

 are capability of giving heavy discharges 

 without sustaining injury, minimum local 

 action, and general freedom from the irregu- 

 larities due to local action. The chloride 

 battery takes its name from the fact that 

 the active material of the plates is made 

 from lead chloride rather than from metallic 

 lead, as in the Plante, or lead oxide as in the 

 pasted batteries. These cells show a high 

 efficiency in practice, small deterioration, 

 capability of holding a charge over consider- 

 able intervals of time, and freedom from 

 short-circuiting, buckling, sulphating, or any 

 of the troubles to which the old lead bat- 

 teries were subject. They are thus seen to 

 possess none of the defects of pasted bat- 

 teries, while they embody all the merits of 

 the Plante cells, without their faults of 

 structural weakness and tedious formation. 

 To-day the extension and use of the storage 

 battery are looked on with growing favor. 



Relations of Moisture and Vegetation. 



M. Edmond Gain has found, in special re- 

 searches on the subject, that the influence of 

 moisture on vegetation varies at different 

 periods of growth of the plant, and that al- 

 ternations of moisture and comparative dry- 

 ness are more advantageous to it than con- 

 stant moisture. The plants that require 

 constant moisture as a factor of their most 

 vigorous growth are relatively few. Nearly 

 all plants need water in order to secure vigor 

 of growth, but require it at different inter- 

 vals in certain precise stages of their vegeta- 

 tion ; and plants which at one time take up 

 water with advantage may suffer much from 

 an equal supply at another time. As a rule, 

 the need of water is urgent when the first 

 leaves are appearing. It then diminishes till 

 just before blossoming, when a large supply 

 is called for. This should be suspended 

 after the flowering season is over, for the 

 fruit is best perfected in a relatively dry 

 medium. If the plants blossom more than 

 once, they need a new supply of water pre- 

 vious to the second flowering. In all the 

 author's experiments those plants which were 

 watered at the two critical seasons of first 

 growth and the beginning of blossoming did 

 as well as those which were constantly wa- 



